N-(1,1 Substituted propynyl)-α-(3,5-substituted phenoxy) alkyl amides

ABSTRACT

N-(1,1 substituted propynyl)-α-(3,5-substituted phenoxy) alkyl amides compounds having the formula ##STR1## in which R 1  and R 2  are independently halogen or alkyl having 1 to 4 carbon atoms; R 3  is alkyl having 1 to 4 carbon atoms; R 4  and R 5  are independently hydrogen or alkyl having 1 to 3 carbon atoms; and their use as herbicides.

This is a continuation, of application Ser. No. 617,454, filed Sept. 29,1975 now U.S. Pat. No. 4,051,184, which is a continuation of applicationSer. No. 464,715, filed Apr. 26, 1974 now abandoned, which is acontinuation of application Ser. No. 353,871, filed Apr. 23, 1973 nowabandoned, which is a continuation of application Ser. No. 157,058,filed June 25, 1971 now abandoned.

This invention relates to certain novel N-(1,1 substitutedpropynyl)-α-(3,5-substituted phenoxy) alkyl amides which are useful asherbicides.

The compounds of the present invention are new compositions of matterand correspond to the formula ##STR2## in which R¹ and R² areindependently halogen, preferably chlorine or alkyl having 1 to 4 carbonatoms, preferably methyl; R³ is alkyl having 1 to 4 carbon atoms,preferably ethyl; R⁴ and R⁵ are independently hydrogen or alkyl having 1to 3 carbon atoms, preferably methyl, more preferably both R⁴ and R⁵ aremethyl.

In the above description of the compounds of this invention, alkylincludes both straight chain and branched chain configurations, forexample, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl ortert.-butyl. The term halogen includes chlorine, bromine, iodine andfluorine.

The closest prior art known to applicants in U.S. Pat. No. 3,272,844.

The compounds of this invention are active herbicides of a general type.That is, they are herbicidally effective against a wide range of plantspecies. The method of controlling undesired vegetation of the presentinvention comprises applying an herbicidally effective amount of theabove-described compounds to the area where control is desired.

An herbicide is used herein to mean a compound which controls ormodifies the growth of plants. By a "growth controlling amount" is meantan amount of compound which causes a modifying effect upon the growth ofplants. Such modifying effects include all deviations from naturaldevelopment, for example, killing, retardation, defoliation,dessiccation, regulation, stunting, tillering, stimulation, dwarfing andthe like. By "plants" it is meant germinating seeds, emerging seedlings,and established vegetation including the roots and above-groundportions.

The compounds of the present invention are prepared by the followinggeneral method.

Reaction No. 1 ##STR3##

Generally, a mole amount of the phenol, a slight mole excess of theα-bromoalkanoic acid and about 3 moles of sodium hydroxide are mixed inwater at about 10° C.-15° C. Then the reaction mixture is heated atreflux for about 2 hours. Thereafter the mixture is cooled and dilutedwith water. The pH of the mixture is adjusted to 8 with 19% hydrochloricacid. The solution is extracted several times with ether followed by apH adjustment to 2 with 19% HCl. An oil separates which is extractedwith ether.

Evaporation of the ether after drying yields the desired product whichis a solid. The solid is purified by recrystalization with cyclohexane.

Reaction No. 2 ##STR4##

First the acid is mixed in benzene. A small amount of the dimethylformamide is added and the slurry is heated. A slight excess of thephosgene reactant is added to the acid mixture in portions. The reactionis complete upon termination of HCl evolution. Evaporation of thereaction mixture yields the desired product, a liquid.

Reaction No. 3 ##STR5##

About equal mole amounts of the amines are dissolved in benzene. Thesolution is cooled to about 10° C. About an equal mole amount of theacid chloride reactant is slowly added to the amine solution at a rateto maintain the temperature between 10° -15° C. After the acid chlorideaddition is complete, the mixture is heated to 45°-50° C. for 1 hour andthen is cooled to room temperature. The mixture is diluted with H₂ O todissolve the amine hydrochloride. Some solid remains undissolved andthis is filtered. The filtrate is washed two times with 10% HCl Witheach wash more solid separates and it is filtered. The organic layer isnext washed two times with 5% Na₂ CO₃ and dried over Mg SO₄. Removal ofsolvent leaves a solid product which is combined with the solid productpreviously removed.

Preparation of the compounds of this invention is illustrated by thefollowing reaction.

EXAMPLE Preparation of N-(1,1 dimethylpropargyl)-α-(3,5-dichlorophenoxy) butyramide ##STR6##

100.0 g. (0.614 moles) of 3,5-dichlorophenol and 112.5 g. (0.675 moles)of α-Bromobutyric acid are mixed and 100 ml. of water is added. Themixture is cooled to 10° C. in an ice water bath and 147.2 g (1.842moles) 50% NaOH is added dropwise over 10°-15° C. The reaction mixtureis warmed to room temperature and then heated at reflux for two hours.After cooling, the mixture is diluted with H₂ O to 600 ml. and the pH isadjusted to 8 with 19% HCl. The aqueous solution is extracted 3 timeswith 150 ml. portions of ether and is then adjusted to pH 2 with 19%HCl. An oil separates which is extracted with ether. Evaporation of theether after drying leaves a white solid, 94.3 g., m.p. 102°-108° C. Thissolid is recrystalized from 250 ml. cyclohexane to give 71.8 g.α-(3,5-dichlorophenoxy) butyric acid m.p. 113°-116° C.

71.8 g. (0.288 moles) of α-(3,5-dichlorophenoxy) butyric acid and 75 ml.of benzene are placed in a 500 ml. flask to which a dropping funnel withdry-ice condenser is attached. The slurry is stirred and the 0.2 ml.dimethyl formamide is added. The mixture is heated to 35° C. and 10 g.of phosgene is condensed into the mixture to initiate reaction. Thestart of the reaction is evidenced by HCl evolution and foaming. 26.0 g.more phosgene is added in 5 gm. increments. At the conclusion of thereaction (HCl evolution ceasing), the reaction mixture is evaporatedleaving a residual liquid α-(3,5-dichlorophenoxy) butyryl chloride 77.6g., N_(D) ²⁰ = 1.5345

164 g. (1.63 moles) triethyl amine and 132 g. (1.58 moles)3-methyl-3-amino-1-butyne are dissolved in 1300 ml. benzene and thesolution is cooled to 10° C. in an ice water bath.

412.9 g. (1.55 moles) α-(3,5-dichlorophenoxy) butyryl chloride dilutedwith 200 ml. benzene is added dropwise to the amine solution. Periodicadditions of benzene (400 ml.) are made in order to adequately stir themixture. After acid chloride addition is complete, the mixture is heatedto 45°-50° C. for 1 hour more and then allowed to come to roomtemperature overnight. The mixture is diluted with 1000 ml. H₂ O todissolve the amine hydrochloride. Some solid remains undissolved andthis is filtered. The filtrate is washed two times with 1000 ml. 10%HCl. With each wash more solid separates and it is filtered. The organiclayer is next washed two times with 5% Na₂ CO₃ and dried over Mg SO.Removal of solvent leaves 377 g. which is combined with the previouslyremoved solid to yield 436 g. of the desired product, m.p. 90°-94° C.

The following is a table of certain selected compounds that arepreparable according to the procedure described hereto. Compound numbersare assigned to each compound and are used through the remainder of theapplication.

                  Table I                                                         ______________________________________                                         ##STR7##                                                                     Compound                                                                      Number   R.sup.1 R.sup.2 R.sup.3   R.sup.4                                                                             R.sup.5                              ______________________________________                                        1        CH.sub.3                                                                              CH.sub.3                                                                              CH.sub.3  CH.sub.3                                                                            CH.sub.3                              2 a)    Cl      Cl      CH.sub.3 CH.sub.2                                                                       CH.sub.3                                                                            CH.sub.3                             3        CH.sub.3                                                                              CH.sub.3                                                                              CH.sub.3 CH.sub.2                                                                       CH.sub.3                                                                            CH.sub.3                             4        Cl      Cl      CH(CH.sub.3).sub.2                                                                      CH.sub.3                                                                            CH.sub.3                             5        Cl      Cl      CH.sub.3 CH.sub.2 CH.sub.2                                                              CH.sub.3                                                                            CH.sub.3                             6        Cl      Cl      CH.sub.3 CH.sub.2                                                                       H     H                                    7        CH.sub.3                                                                              CH.sub.3                                                                              CH.sub.3 CH.sub.2                                                                       H     H                                    ______________________________________                                         a) Prepared in Example 1.                                                

Herbicidal Screening Tests

As previously mentioned, the herein described compounds produced in theabove-described manner are phytotoxic compounds which are useful andvaluable in controlling various plant species. Selected compounds ofthis invention are tested as herbicides in the following manner.

Pre-emergence herbicide test. On the day preceding treatment, seeds ofseven different weed species are planted in individual rows using onespecies per row across the width of the flat. The seeds used are hairycrabgrass (Digitaris sanguinalis (L.) Scop.), yellow foxtail (Setariaglauca (L.) Beauv.), watergrass Echinochloa crusgalli (L.) Beauv.),California red oat (Auena sativa (L.), redroot pigweed (Amaranthusretroflexs (L.) Indian mustard (Brassica juncea (L.) Coss.) and curlydock (Rumex crispus (L.). Ample seeds are planted to give about 20 to 50seedlings per row, after emergence, depending upon the size of theplants. The flats are watered after planting. The spraying solution isprepared by dissolving 50 mg. of the test compound in 3 ml. of asolvent, such as acetone, containing 1% Tween 20® (polyoxyethylenesorbitan monolaurate). The following day each flat is sprayed at therate of 20 pounds of the candidate compound per 80 gallons of solutionper acre. An atomizer is used to spray the solution onto the soilsurface. The flats are placed in a greenhouse at 80° F. and wateredregularly. Two weeks later the degree of weed control is determined bycomparing the amount of germination and growth of each weed in thetreated flats with the same weeds in several untreated control flats.The rating system is as follows:

- = no significant injury (0-15 percent control)

+ = slight injury (25-35 percent control)

++ = moderate injury (55-65 percent control)

+++ = severe injury or death (85-100 percent control)

An activity index is used to represent the total activity of all sevenweed species. It is the sum of the number of plus marks, so that anactivity index of 21 represents almost complete control of all sevenweeds. The results of this test are reported in Table II.

Post-emergence herbicide test. Seeds of five weed species includinghairy crabgrass, watergrass, California red oats, Indian mustard, andcurly dock and one crop, pinto beans (Phaseolus vulgaris), are plantedin flats as described above for pre-emergence screening. The flats areplaced in the greenhouse at 72°-85° F. and watered daily with asprinkler. About 10 to 14 days after planting when the primary leaves ofthe bean plant are almost fully expanded and the first trifoliate leavesare just starting to form, the plants are sprayed. The spray is preparedby weighing out 50 mg. of the test compound, dissolving it in 5 ml. ofacetone containing 1% Tween 20® R (polyoxyethylene sorbitan monolaurate)and then adding 5 ml. of water. The solution is sprayed on the foliageusing an atomizer. The spray concentration is 0.5% and the rate would beapproximately 20 pounds per acre if all of the spray was retained on theplant and the soil, but some spray is lost so it is estimated that theapplication rate is approximately 12.5 pounds per acre.

Beans are used to detect defoliants and plant growth regulators. Thebeans are trimmed to two or three plants per flat by cutting off theexcess weaker plants several days before treatment. The treated plantsare placed back in the greenhouse and care is taken to avoid sprinklingthe treated foliage with water for three days after treatment. Water isapplied to the soil by means of a slow stream from a watering hosetaking care not to wet the foliage.

Injury rates are recorded 14 days after treatment. The rating system isthe same as described above for the pre-emergence test where (-), (+),(++), and (+++) are used for the different rates of injury and control.The injury symptoms are also recorded. The maximum activity index forcomplete control of all the species in the post-emergence screening testis 18 which represents the sum of the plus marks obtained with the sixplant species used in the test. The herbicide activity is shown in TableII.

                  TABLE II                                                        ______________________________________                                        HERBICIDAL ACTIVITY                                                           SCREENING RESULTS                                                             Herbicidal Activity Index**                                                   Compound    Pre-emergence Post-emergence                                      Number      (20 lb/A)     (12.5 lb/A)                                         ______________________________________                                        1           21            17                                                  2           21            15                                                  3           21            15                                                  4           12             3                                                  5           18            13                                                  6           20            15                                                  7           21            15                                                  ______________________________________                                         **21 = 85-100% control of all seven plant species tested pre-emergence.       18 = 85-100% control of all six plant species tested post-emergence.     

The compounds of the present invention are used as pre-emergence orpost-emergence herbicides and are applied in a variety of ways atvarious concentrations. In practice, the compounds herein defined areformulated into herbicidal compositions, by admixture, in herbicidallyeffective amounts, with the adjuvants and carriers normally employed forfacilitating the dispersion of active ingredients for agriculturalapplications, recognizing the fact that the formulation and mode ofapplication of a toxicant may affect the activity of the materials in agiven application. Thus, these active herbicidal compounds may beformulated as granules of relatively large particle size, as wettablepowders, as emulsifiable concentrates, as powdery dusts, as solutions oras any of several other known types of formulations, depending upon thedesired mode of application. Preferred formulations for both pre- andpost-emergence herbicidal applications are wettable powders,emulsifiable concentrates and granules. These formulations may containas little as about 0.5% to as much as about 95% or more by weight ofactive ingredient. The amount applied depends upon the nature of theseeds or plants to be controlled and the rate of application varies from1/8 to approximately 50 pounds per acre.

Wettable powders are in the form of finely divided particles whichdisperse readily in water or other dispersant. The wettable powder isultimately applied to the soil either as a dry dust or as a dispersionin water or other liquid. Typical carriers for wettable powders includefuller's earth, kaolin clays, silicas and other readily wet organic orinorganic diluents. Wettable powders normally are prepared to containabout 5% to about 95% of the active ingredient by weight and usuallyalso contain a small amount of wetting, dispersing or emulsifying agentto facilitate wetting and dispersion.

Emulsifiable concentrates are homogeneous liquid compositions which aredispersible in water or other dispersant, and may consist entirely ofthe active compound with a liquid or solid emulsifying agent, or mayalso contain a liquid carrier, such as xylene, heavy aromatic naphthas,isophorone and other non-volatile organic solvents. For herbicidalapplication, these concentrates are dispersed in water or other liquidcarrier and normally applied as a spray to the area to be treated. Thepercentage by weight of the essential active ingredient may varyaccording to the manner in which the composition is to be applied, butin general comprises about 0.5% to 95% of active ingredient by weight ofthe herbicidal composition.

Granular formulations, wherein the toxicant is carried on relativelycoarse particles, are usually applied without dilution to the area inwhich suppression of vegetation is desired. Typical carriers forgranular formulations include sand, fuller's earth, bentonite clays,vermiculite, perlite and other organic or inorganic materials whichabsorb or which may be coated with the toxicant. Granular formulationsnormally are prepared to contain about 5% to about 25% of activeingredient and may also contain small amounts of other ingredients whichmay include surface-active agents such as wetting agents, dispersingagents or emulsifiers; oils such as heavy aromatic naphthas, kerosene orother petroleum fractions, or vegetable oils; and/or stickers such asdextrins, glue or synthetic resins.

Typical wetting, dispersing or emulsifying agents used in agriculturalformulations include, for example, the alkyl and alkylaryl sulfonatesand sulfates and their sodium salts; polyhydric alcohols; and othertypes of surface-active agents, many of which are available in commerce.The surface-active agent, when used, normally comprises from 0.1% to 15%by weight of the herbicidal composition.

Dusts, which are free-flowing admixtures of the active ingredient withfinely divided solids such as talc, clays, flours, and other organic andinorganic solids which act as dispersants and carriers for the toxicant,are useful formulations for soil-incorporating applications.

Pastes, which are homogeneous suspensions of a finely divided solidtoxicant in a liquid carrier such as water or oil, are employed forspecific purposes. These formulations normally contain about 5% to about95% of active ingredient by weight, and may also contain small amountsof a wetting, dispersing or emulsifying agent to facilitate dispersion.For application, the pastes are normally diluted and applied as a sprayto the area to be affected.

Other useful formulations for herbicidal applications include simplesolutions of the active ingredient in a dispersant in which it iscompletely soluble at the desired concentration, such as acetone,alkylated naphthalenes, xylene or other organic solvents. Pressurizedsprays, typically aerosols, wherein the active ingredient is dispersedin finely-divided form as a result of vaporization of a low boilingdispersant solvent carrier, such as the Freons, may also be used.

The phytotoxic compositions of this invention are applied to the plantsin the conventional manner. Thus, the dust and liquid compositions canbe applied to the plant by the use of power-dusters, boom and handsprayers and spray dusters. The compositions can also be applied fromairplanes as a dust or a spray because they are effective in very lowdosages. In order to modify or control growth of germinating seeds oremerging seedlings, as a typical example, the dust and liquidcompositions are applied to the soil according to convention methods andare distributed in the soil to a depth of at least 1/2 inch below thesoil surface. It is not necessary that the phytotoxic compositions to beadmixed with the soil particles since these compositions can also beapplied merely by spraying or sprinkling the surface of the soil. Thephytotoxic compositions of this invention can also be applied byaddition to irrigation water supplied to the field to be treated. Thismethod of application permits the penetration of the compositions intothe soil as the water is absorbed therein. Dust compositions, granularcompositions or liquid formulations applied to the surface of the soilcan be distributed below the surface of the soil by conventional meanssuch as discing, dragging or mixing operations.

The phytotoxic compositions of this invention can also contain otheradditaments, for example, fertilizers, pesticides and the like, used asadjuvant or in combination with any of the above-described adjuvants.Other phytotoxic compounds useful in combination with theabove-described compounds include, for example,2,4-dichlorophenoxyacetic acids, 2,4,5-trichlorophenoxyacetic acid,2-methyl-4-chlorophenoxyacetic acid and the salts, esters and amidesthereof; triazine derivatives, such as2,4-bis(3-methoxypropylamino)-6-methylthio-s-triazine,2-chloro-4-ethylamino-6-isopropylamino-s-triazine, and2-ethylamino-4-isopropylamino-6-methylmercapto-s-triazine; ureaderivatives, such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea and3-(p-chlorophenyl)-1,1-dimethyl urea: and acetamides such asN,N-diallyl-α-chloroacetamide, and the like; benzoic acids such as3-amino-2,5-dichlorobenzoic; thiocarbamates, such as S-propyldipropylthiocarbamate, S-ethyldipropylthiocarbamate, S-ethylcyclohexylethyl thiocarbamate, S-ethylhexahydro-1H-azepine-1-carbothioate and the like;4-(methylsulfonyl)-2,6-dinitro-N,N-substituted anilines, such as4-(methylsulfonyl)-2,6-dinitro-N,N-di-n-propyl aniline,4-trifluoromethyl-2,6-dinitro-N,N-substituted anilines, such as4-trifluoromethyl-2,6-dinitro-N,N-di-n-propyl aniline and4-trifluoromethyl-2,6-dinitro-N-ethyl-N-n-butyl aniline. Fertilizersuseful in combination with the active ingredients include, for example,ammonium nitrate, urea and superphosphate. Other useful additamentsinclude materials in which plant organisms take root and grow such ascompost, manure, humus, sand and the like.

The concentration of a compound of the present invention, constitutingan effective amount of the best mode of administration in the utilitydisclosed is readily determinable by those skilled in the art.

It is claimed:
 1. Compounds of the formula ##STR8## in which R¹ and R²are both chlorine or both methyl; R⁴ is hydrogen or methyl and R⁵ ishydrogen, methyl or ethyl provided that R⁴ and R⁵ are both not methyl.2. The compound of claim 1 in which R¹ is methyl, R² is methyl, R⁴ ishydrogen, and R⁵ is hydrogen.
 3. The compound of claim 1 in which R¹ ischlorine, R² is chlorine, R⁴ is hydrogen and R⁵ is hydrogen.
 4. Thecompound of claim 1 in which R¹ is methyl, R² is methyl, R⁴ is methyland R⁵ is hydrogen.
 5. The compound of claim 1 in which R¹ is chloro, R²is chloro, R⁴ is methyl and R⁵ is ethyl.
 6. The compound of claim 1 inwhich R¹ is methyl, R² is methyl, R⁴ is methyl and R⁵ is ethyl.